A. Field of the Invention
This invention relates generally to oscillators and more particularly to a voltage controlled oscillator compensated to minimize modulation sensitivity variations over a wide frequency bandwidth.
B. Description of the Prior Art
It is frequently necessary in the implementation of a phase-locked loop for a frequency synthesizer or receiver local oscillator, and in other applications such as FM generators, data transmitters, and telemetry data links, to provide a voltage controlled oscillator whose output frequency can be controlled over a wide bandwidth. Particularly in implementing a synthesized radio transceiver, a wide bandwidth VCO is desirable to maximize the number of channels of operation. However, past attempts to provide wide bandwidth operation have resulted in variations in modulation sensitivity over the operating frequency range. Until now attempts to solve this problem involved utilizing an audio level switch or potentiometer to compensate for sensitivity changes, which caused discrete sensitivity changes or required adjustment by an operator. This resulted in inaccurate compensation and in unacceptable splatter performance.